Collapse of Holocene mangrove ecosystems along the coastline of Oman

2020 ◽  
pp. 1-25
Author(s):  
Valeska Decker ◽  
Michaela Falkenroth ◽  
Susanne Lindauer ◽  
Jessica Landgraf ◽  
Zahra Al-Lawati ◽  
...  
Keyword(s):  
Sea Level ◽  
Human Interaction ◽  
Archaeological Sites ◽  
Climate Conditions ◽  
Sea Levels ◽  
Sea Level Variation ◽  
Mangrove Ecosystems ◽  
Decadal Scale ◽  
Close Proximity ◽  
Interdisciplinary Inquiry

Abstract Sedimentological, geochemical, and paleontological investigations of the coastline of northeastern Oman have provided the authors with an in-depth insight into Holocene sea levels and climate conditions. The spatial distribution and species assemblage of mangrove ecosystems are analyzed. These ecosystems are sensitive to changes in sea level and precipitation and thus reflect ecological conditions. The close proximity to archaeological sites allows us to draw conclusions regarding human interaction with the mangrove ecosystems. Our interdisciplinary inquiry reveals that the mangrove ecosystems along the east coast of Oman collapsed ~6000 cal yr BP on a decadal scale. There is no sedimentological evidence for a mid-Holocene sea-level highstand. The ecosystem collapse was not caused by sea-level variation or anthropogenic interferences; rather, it was the consequence of reduced precipitation values related to a southward shift of the Intertropical Convergence Zone. This resulted in a decrease of freshwater input and an increase in soil salinity. Further, the aridification of the area caused increased deflation and silting up of the lagoons.

scholarly journals SEA LEVEL CHANGES ALONG THE COASTS OF KEA ISLAND AND PALEOGEOGRAPHICAL COASTAL RECONSTRUCTION OF ARCHAEOLOGICAL SITES

2017 ◽  
Vol 43 (1) ◽  
pp. 453 ◽  
Author(s):  
N.D Mourtzas
Keyword(s):  
Sea Level ◽  
Human Activity ◽  
Human Activities ◽  
Archaeological Sites ◽  
Classical Period ◽  
Sea Level Changes ◽  
Coastal Morphology ◽  
Sea Levels

Sea level changes during the Upper Holocene submerged the coasts of Kea in three different phases about 5.50m, 3.90m and 1.50m respectively below the contemporary sea level thus causing sea transgression along the shores of Kea, which varied from 8m to 78m depending on the coastal morphology. These changes caused the alteration of the earlier morphology at coastal archaeological sites of the Island, as the prehistoric settlement of Ayia Irini and Classical period port of Karthaia, as well as, submerged under the sea areas of coastal human activity during antiquity, as the ancient schist quarry at Spathi bay. The study of historical, geomorphological and sedimentological data indicative of previous sea levels allow the paleogeographical reconstruction of the coasts during the period of human activities in these areas.

Sea-level change and the archaeology of early Venice

Antiquity ◽  
1999 ◽  
Vol 73 (280) ◽  
pp. 303-312 ◽  
Author(s):  
A. J. Ammerman ◽  
C. E. McClennen ◽  
M. de Min ◽  
R. Housley
Keyword(s):  
Sea Level ◽  
Sea Level Change ◽  
Archaeological Sites ◽  
Archaeological Investigation ◽  
Sea Levels ◽  
Level Change ◽  
The Subject ◽  
Rising Sea Levels ◽  
New Evidence ◽  
Insight Into

The threatened city of Venice, plauged by rising sea levels and subsiding ground, has been the subject of recent archaeological investigation. Studies of buried archaeological sites yield new evidence on trends in sea-level change for the Lagoon of Venice and provide important insight into how early habitation responded to such change.

BATTLING WATER: THE FRONTIERS OF ARCHAEOLOGICAL EXCAVATIONS AT BUTRINT (1928–2014)

2017 ◽  
Vol 112 ◽  
pp. 379-412 ◽  
Author(s):  
David R. Hernandez
Keyword(s):  
Sea Level ◽  
Water Table ◽  
Second Century ◽  
Archaeological Sites ◽  
Archaeological Research ◽  
Urban Centre ◽  
Sea Levels ◽  
The Past ◽  
The Impact

This article examines the impact of sea level (water table) on archaeological research at Butrint (Bouthrotos/Buthrotum) from 1928 to 2014. Rising relative sea levels over the past three thousand years have shaped the actions not only of its ancient inhabitants but also of its modern archaeologists, conditioning archaeological objectives, fieldwork and the interpretation of the archaeological record. Butrint's first archaeologist, Luigi M. Ugolini, considered groundwater to be a detriment to archaeological research at the site. Subsequent archaeologists have viewed it as the limit of excavation. Battling water at Butrint, archaeologists have shared a universal perception of groundwater as an enemy and thereby have overlooked one of Butrint's most important areas of archaeological research – its wetland and wet-site archaeology. The Roman Forum Excavations (RFE) Project undertook the first wet-site excavations at Butrint, reaching depths of up to four metres below the water table in stratigraphic excavations in the ancient urban centre. The results demonstrate that the ancient urban centre formed much later than is presently thought: the lower city emerged as dryland in the second half of the second century bc. Relative sea levels have increased since antiquity at many coastal regions in the Mediterranean, often submerging archaeological sites either partially or completely. Butrint is a case study that shows how sea level is inextricably tied to archaeological practice and interpretation at this major ancient Mediterranean seaport.

Extreme sea levels at the Finnish coast due to large-scale wind storms

2021 ◽  
Author(s):  
Jani Särkkä ◽  
Jani Räihä ◽  
Mika Rantanen ◽  
Kirsti Jylhä
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Large Scale ◽  
Low Pressure ◽  
The Baltic Sea ◽  
Sea Levels ◽  
Sea Level Variation ◽  
Level Model ◽  
The Baltic ◽  
Low Pressure Systems

<p>In the Baltic Sea, the short-term sea level variation might be several meters, even if the tides in the Baltic Sea are negligible. The short-term sea level fluctuations are caused by passing wind storms, inducing sea level variation through wind-induced currents, inverse barometric effect and seiches. Due to the shape of the Baltic Sea with several bays, the highest sea levels are found in the ends of bays like the Gulf of Finland and the Bothnian Bay. The sea level extremes caused by the large-scale windstorms depend strongly on the storm tracks. Within the natural climatic variability during the past centuries, there have most likely been higher sea level extremes than the extreme values found in the tide gauge records.</p><p>To study this variability of sea levels, induced by varying tracks of the passing windstorms, we construct an ensemble of synthetic low-pressure systems. In this ensemble, the parameters of the low-pressure systems (e.g. point of origin, velocity of the center of the system and depth of the pressure anomaly) are varied. The ensemble of low pressure systems is used as an input to a numerical sea level model based on shallow-water hydrodynamic equations. The sea level model is fast to calculate, enabling a study of a large set of varying storm tracks. As a result we have an ensemble of simulated sea levels. From the simulation results we can determine the low-pressure system that induces the highest sea level on a given location on the coast. We concentrate our studies on the Finnish coast, but the method can be applied to the entire Baltic coast. </p>

scholarly journals Probabilistic Tsunami Hazard Assessment in Meso and Macro Tidal Areas. Application to the Cádiz Bay, Spain

2021 ◽  
Vol 9 ◽  
Author(s):  
Mauricio González ◽  
José A. Álvarez-Gómez ◽  
Íñigo Aniel-Quiroga ◽  
Luis Otero ◽  
Maitane Olabarrieta ◽  
...  
Keyword(s):  
Time Series ◽  
Monte Carlo ◽  
Sea Level ◽  
Tsunami Hazard ◽  
Historical Records ◽  
Level Variation ◽  
Sea Levels ◽  
Sea Level Variation ◽  
Cadiz Bay ◽  
Seismic Catalogs

Tsunami hazard can be analyzed from both deterministic and probabilistic points of view. The deterministic approach is based on a “credible” worst case tsunami, which is often selected from historical events in the region of study. Within the probabilistic approach (PTHA, Probabilistic Tsunami Hazard Analysis), statistical analysis can be carried out in particular regions where historical records of tsunami heights and runup are available. In areas where these historical records are scarce, synthetic series of events are usually generated using Monte Carlo approaches. Commonly, the sea level variation and the currents forced by the tidal motion are either disregarded or considered and treated as aleatory uncertainties in the numerical models. However, in zones with a macro and meso tidal regime, the effect of the tides on the probability distribution of tsunami hazard can be highly important. In this work, we present a PTHA methodology based on the generation of synthetic seismic catalogs and the incorporation of the sea level variation into a Monte Carlo simulation. We applied this methodology to the Bay of Cádiz area in Spain, a zone that was greatly damaged by the 1755 earthquake and tsunami. We build a database of tsunami numerical simulations for different variables: faults, earthquake magnitudes, epicenter locations and sea levels. From this database we generate a set of scenarios from the synthetic seismic catalogs and tidal conditions based on the probabilistic distribution of the involved variables. These scenarios cover the entire range of possible tsunami events in the synthetic catalog (earthquakes and sea levels). Each tsunami scenario is propagated using the tsunami numerical model C3, from the source region to the target coast (Cádiz Bay). Finally, we map the maximum values for a given probability of the selected variables (tsunami intensity measures) producing a set of thematic hazard maps. 1000 different time series of combined tsunamigenic earthquakes and tidal levels were synthetically generated using the Monte Carlo technique. Each time series had a 10000-year duration. The tsunami characteristics were statistically analyzed to derive different thematic maps for the return periods of 500, 1000, 5000, and 10000 years, including the maximum wave elevation, the maximum current speed, the maximum Froude number, and the maximum total forces.

Supplement to State of the Climate in 2006

2007 ◽  
Vol 88 (6) ◽  
pp. S1-S135 ◽  
Author(s):  
A. Arguez
Keyword(s):  
Tropical Cyclone ◽  
Sea Level ◽  
El Niño ◽  
El Nino ◽  
Polar Regions ◽  
Sea Ice Extent ◽  
Indian Ocean Dipole Mode ◽  
Climate Conditions ◽  
Sea Levels ◽  
Global Mean Sea Level

Abstract The State of the Climate in 2006 report summarizes the year's weather and climate conditions, both globally and regionally. In addition, the year is placed into a long-term climatological context. Furthermore, notable events are also discussed. Overall global temperatures were fifth or sixth warmest on record, depending on the dataset, continuing an upward trend in temperatures. Many countries and regions experienced their record warmest year (or tied for warmest), including Spain, the Netherlands, the United Kingdom, and China, as well as parts of Australia and Canada. In many regions, the warmth in 2006 is statistically indistinguishable from the record warmth in 1998. However, 1998 was influenced by the unprecedented warming associated with the record 1997/98 El Niño, whereas 2006 was marked by a 2005/06 La Niña that transitioned into a weak-to-moderate 2006/07 El Niño. Consistent with the warming, sea ice extent in both polar regions reached record or near-record minima. In addition, Antarctic ozone concentrations reached an all-time minimum. Also, carbon dioxide measurements increased in the atmosphere by 2.3 parts per million (ppm) in 2006 to reach a global average of 381.1 ppm. In the global oceans, sea levels were above average for ∼80% of the ocean. The global mean sea level anomaly change of +6 mm from 2005 was the highest increase since the altimeter record began in 1993. Relative sea level change was also the highest ever recorded. Significant heat flux and current anomalies were observed in the regions of the 2006 El Niño and Indian Ocean dipole mode event. Despite the warmth around the globe, tropical cyclone counts were near average. However, Tropical Cyclone Larry made landfall in northern Australia as one of the most intense storms in decades. Following the record Atlantic hurricane season of 2005, the 2006 season was very quiet.

scholarly journals Economic damages from Hurricane Sandy attributable to sea level rise caused by anthropogenic climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin H. Strauss ◽  
Philip M. Orton ◽  
Klaus Bittermann ◽  
Maya K. Buchanan ◽  
Daniel M. Gilford ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
The United States ◽  
Hurricane Sandy ◽  
Water Levels ◽  
Anthropogenic Climate Change ◽  
Economic Damage ◽  
Sea Levels

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.

Records of sea-level highstand over the Meghalayan age/late Holocene from uranium-series ages of beachrock in Weizhou Island, northern South China Sea

The Holocene ◽  
2021 ◽  
pp. 095968362110332
Author(s):  
Tingli Yan ◽  
Kefu Yu ◽  
Rui Wang ◽  
Wenhui Liu ◽  
Leilei Jiang
Keyword(s):  
South China Sea ◽  
Sea Level ◽  
South China ◽  
Intertidal Zone ◽  
Meteoric Water ◽  
Northern South China Sea ◽  
Water Environment ◽  
Sea Levels ◽  
China Sea ◽  
Micro Structures

Beachrock is considered a good archive for past sea-levels because of its unique formation position (intertidal zone). To evaluate sea-level history in the northern South China Sea, three well-preserved beachrock outcrops (Beigang, Gongshanbei, and Hengling) at Weizhou Island, northern South China Sea were selected to examine their relative elevation, sedimentological, mineralogical, and geochemical characteristics. Acropora branches with well-preserved surface micro-structures were selected from the beachrocks and used to determine the ages of these beachrocks via U-series dating. The results show that the beachrocks are composed of coral reef sediments, terrigenous clastics, volcanic clastics, and various calcite cements. These sediments accumulated in the intertidal zone of Weizhou Island were then cemented in a meteoric water environment. The U-series ages of beachrocks from Beigang, Gongshanbei, and Hengling are 1712–768 ca. BP, 1766–1070 ca. BP, and 1493–604 ca. BP (before 1950 AD) respectively. Their elevations are 0.91–1.16 m, 0.95–1.24 m, and 0.82–1.17 m higher than the modern homologous sedimentary zones, respectively. Therefore, we concluded that the sea-level in the Meghalayan age (1766–604 ca. BP) was 0.82–1.24 m higher than the present, and that the sea-level over this period showed a declining trend.

scholarly journals Flooding Conditions at Aveiro Port (Portugal) within the Framework of Projected Climate Change

2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Américo Soares Ribeiro ◽  
Carina Lurdes Lopes ◽  
Magda Catarina Sousa ◽  
Moncho Gomez-Gesteira ◽  
João Miguel Dias
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Climate Change Impacts ◽  
Storm Surges ◽  
Historical Period ◽  
Return Periods ◽  
Wave Regime ◽  
Mean Sea Level ◽  
Sea Levels ◽  
Far Future

Ports constitute a significant influence in the economic activity in coastal areas through operations and infrastructures to facilitate land and maritime transport of cargo. Ports are located in a multi-dimensional environment facing ocean and river hazards. Higher warming scenarios indicate Europe’s ports will be exposed to higher risk due to the increase in extreme sea levels (ESL), a combination of the mean sea level, tide, and storm surge. Located on the west Iberia Peninsula, the Aveiro Port is located in a coastal lagoon exposed to ocean and river flows, contributing to higher flood risk. This study aims to assess the flood extent for Aveiro Port for historical (1979–2005), near future (2026–2045), and far future (2081–2099) periods scenarios considering different return periods (10, 25, and 100-year) for the flood drivers, through numerical simulations of the ESL, wave regime, and riverine flows simultaneously. Spatial maps considering the flood extent and calculated area show that most of the port infrastructures' resilience to flooding is found under the historical period, with some marginal floods. Under climate change impacts, the port flood extent gradually increases for higher return periods, where most of the terminals are at high risk of being flooded for the far-future period, whose contribution is primarily due to mean sea-level rise and storm surges.

scholarly journals Twenty-first century response of Petermann Glacier, northwest Greenland to ice shelf loss

2020 ◽  
pp. 1-11
Author(s):  
Emily A. Hill ◽  
G. Hilmar Gudmundsson ◽  
J. Rachel Carr ◽  
Chris R. Stokes ◽  
Helen M. King
Keyword(s):  
Sea Level ◽  
First Century ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Sea Levels ◽  
Grounding Line ◽  
Global Mean Sea Level ◽  
Near Future ◽  
Global Mean ◽  
Large Sections

Abstract Ice shelves restrain flow from the Greenland and Antarctic ice sheets. Climate-ocean warming could force thinning or collapse of floating ice shelves and subsequently accelerate flow, increase ice discharge and raise global mean sea levels. Petermann Glacier (PG), northwest Greenland, recently lost large sections of its ice shelf, but its response to total ice shelf loss in the future remains uncertain. Here, we use the ice flow model Úa to assess the sensitivity of PG to changes in ice shelf extent, and to estimate the resultant loss of grounded ice and contribution to sea level rise. Our results have shown that under several scenarios of ice shelf thinning and retreat, removal of the shelf will not contribute substantially to global mean sea level (<1 mm). We hypothesize that grounded ice loss was limited by the stabilization of the grounding line at a topographic high ~12 km inland of its current grounding line position. Further inland, the likelihood of a narrow fjord that slopes seawards suggests that PG is likely to remain insensitive to terminus changes in the near future.

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